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Method for producing contrast agent for optical imaging

Inactive Publication Date: 2012-03-01
CANON KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0011]Accordingly, an object of the present invention is to provide a method for preparing a contrast agent for optical imaging with a high content of a hydrophilic dye having a sulfonate group by increasing the solubility of a hydrophilic dye having a sulfonate group in a hydrophobic solvent having low solubility in water.
[0013]The inventors of the present invention have found that, as compared with the case where a hydrophilic dye having a sulfonate group alone is dissolved, the hydrophilic dye can be dissolved at a higher concentration in a hydrophobic solvent having low solubility in water when it is dissolved after a lipid having a positively charged site is added thereto. In the method for producing a contrast agent for optical imaging according to the present invention, a hydrophilic dye having a sulfonate group and a lipid having a positively charged site are dissolved in a hydrophobic solvent, whereby the hydrophilic dye can be dissolved at a high concentration without using a hydrophilic solvent. Therefore, a contrast agent for optical imaging with a higher content of a hydrophilic dye having a sulfonate group can be produced.

Problems solved by technology

On the other hand, however, ICG is hardly soluble in a hydrophobic solvent, which has low polarity and is hardly miscible with water.
However, the inventors of the present invention found that, when an ICG solution and water were mixed, a large amount of ICG was leaked into water.

Method used

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  • Method for producing contrast agent for optical imaging
  • Method for producing contrast agent for optical imaging
  • Method for producing contrast agent for optical imaging

Examples

Experimental program
Comparison scheme
Effect test

example 1

Solubility of ICG in Chloroform when Phospholipid was Added

[0077]Double molar equivalents of a phospholipid was added to 5.5 mg of ICG. As the phospholipid, DSPC, DOPE, DSPE or DPPS was used. These ICG-phospholipid mixtures were dissolved in 3 mL of a methanol-chloroform (1:2) mixture. A control was further prepared by dissolving ICG alone in 3 mL of a methanol-chloroform (1:2) mixture. Subsequently, pressure of these solutions was reduced at 40° C. to distill off the solvent. Each of the ICG-phospholipid mixtures evaporated to dryness were dissolved in 2 mL of chloroform and filtered with a filter having a pore size of 0.2 μm. The filtrates were diluted 100-fold with chloroform. Using a quartz cell having a light path of 1 cm, absorbances were measured wavelengths between 550 and 900 nm in intervals of 1 nm. The sums of absorbances wavelengths between 550 and 900 nm are shown in FIG. 2 as the absorption curve integral values.

[0078]Compared with the case where ICG alone was dissolve...

example 2

Solubility of ICG in Dichloromethane when Phospholipid was Added

[0080]2 molar equivalents of a phospholipid was added to 5.5 mg of ICG. As the phospholipid, DSPC or DOPE was used. Each of these ICG-phospholipid mixtures was dissolved in 2 mL of dichloromethane. Controls were brepared by dissolving in 10 G in methanol or dichloromethane. All these 10 G solutions were filtered with a filter having a pore size of 0.2 μm and then diluted 500-fold with dichloromethane. The absorption curve integral values obtained in the same manner as in Example 1 are shown in FIG. 3.

[0081]Compared with the cases where ICG alone was dissolved in dichloromethane, the solubility of ICG in dichloromethane was improved approximately six times when DSPC or DOPE was added, and ICG was dissolved to a similar extent as the ICG dissolved methanol. Furthermore, the absorption curve integral values of the ICG-methanol solution (2.75 mg / mL=3.5 mM) and the absorption curve integral values of the ICG-dichloromethane ...

reference example 1

Leakage of ICG Dissolved in Dichloromethane-Methanol Mixture into Water

[0082](Preparation of ICG Solution)

[0083]11 mg of ICG was dissolved in 4 rut of a dichloromethane-methanol (1.2) mixture or a dichloromethane-methanol (3:1) mixture, and the mixture was filtered with a filter having a pore size of 0.2 μm. The obtained filtrates were designated as ICG solutions (1) and (2).

[0084]DSPC was added to 11 mg of ICG in a molar ratio of 1:2, and the mixture was dissolved in 3 mL of a methanol-chloroform (1:2) mixture. Subsequently, the solvent of this solution was distilled off under reduced pressure at 40° C. The ICG-DSPC mixture evaporated to dryness was dissolved in 4 mL of dichloromethane and, the mixture was filtered with a filter having a pore size of 0.2 μm. The filtrate was designated as ICG solution (3).

[0085]Each of the ICG solutions (1) to (3) was diluted 500-fold with dichloromethane, and absorption curve integral values were obtained in the same manner as in Example 1. The re...

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Abstract

A contrast agent for optical imaging is produced by preparing a composition containing a hydrophilic dye having a sulfonate group, a hydrophobic solvent, a lipid having a positively charged site, and a polymerizable monomer or a prepolymer, dispersing the composition into water, and polymerizing the polymerizable monomer or the prepolymer.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a method for preparing a contrast agent containing a hydrophilic dye such as indocyanine green.[0003]2. Description of the Related Art[0004]As methods for visualizing in-vivo information for the purpose of diagnosis of a disease, bioimaging is performed using X-rays, nuclear magnetic resonance, ultrasonic waves or the like. In recent years, particularly as a method for conducting a diagnosis noninvasively, imaging methods such as a fluorescence method using a near-infrared light and photoacoustic tomography have been drawing attention.[0005]Fluorescence methods are widely used for various imaging tests. In a fluorescence method, a fluorescent dye is irradiated with a light, and a fluorescence emitted by the dye is detected. Photoacoustic tomography is a method of detecting an acoustic wave generated by volume expansion caused by a heat released from a molecule that has absorbed a light e...

Claims

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Application Information

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IPC IPC(8): A61K49/00A61P43/00
CPCA61K49/0032A61K49/0071A61K49/0034A61P43/00
Inventor KATO, KOUICHIYUASA, SATOSHIFUKUI, TATSUKI
Owner CANON KK
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